Trustworthy people in the church could accept and sensitively share secrets about where the IRA's "Disappeared" victims are buried, the head of Irish Catholicism said.

Four people abducted and killed by republicans who suspected them of being British informers have still not been found decades later.

Archbishop of Armagh Eamon Martin said there was an urgent need to develop truth-telling mechanisms about the past violence.

He added: "There must be so many people walking around today who know in their hearts that the information that they have locked down inside them is capable of unlocking the uncertainty and grief of families."

Despite extensive searches, the bodies have never been found of four out of 16 people targeted by the IRA during the conflict.

The hunt has been led by the Independent Commission for the Location of Victims' Remains, established in 1999 by an agreement between the British and Irish governments to obtain information in strictest confidence that may lead to where the bodies are buried.

Archbishop Martin added: "For our part, we need to find a mechanism of truth and information retrieval which will allow more of these people to come forward so that many more families can be set free from the agony of waiting and wondering, 'why?'

"Even in the absence of a formal mechanism, I am confident that there are trustworthy people in society and in the churches who would be willing, and could be empowered and enabled, to accept and sensitively share information in this regard."